1. Field of the Invention
The present invention relates to braking apparatus and more particularly to braking apparatus which interact with suspension members to counteract the tendency of the front suspension of a vehicle to "dive" when the braking mechanism is applied.
2. General Background
Front suspension members on vehicles such as automobiles and motorcycles generally comprise shock absorbers which utilize coil springs and hydraulic fluid chambers to provide a smooth ride for the operator and passengers of the vehicle by damping the impact of irregularities encountered in the road surface. Upon application of the brakes while traveling, the inertia or forward momentum of the vehicle tends to cause compression of the front suspension and diving of the front of the vehicle. The amount of dive is directly proportional to the braking force applied and has the adverse effects of reducing effective suspension travel, effecting the weight distribution and pitch or level attitude of the vehicle, and, therefore, affecting the steering geometry and handling characteristics of the vehicle. The above has been recognized in the art and a variety of approaches have been directed toward the problem.
Japanese Pat. No. 56-25008 entitled "Anti-Dive Device for Motorcycle" discloses a device which feeds braking hydraulic pressure into an annular hydraulic pressure chamber and presses an elastic braking material against the fork pipe to prevent sinking action of the fork pipe when sudden braking is applied.
U.S. Pat. No. 4,392,664 entitled "Front Fork Of Motorcycle" discloses a fork assembly wherein the bottom casing is filled with oil and has a pipe seat anchored in the bottom portion of the casing with its upper end slidably fitted to the fork pipe. An oil passage providing communication between the inside and outside of the pipe seat has a plunger equipped with a valve for opening and closing the oil passage which is adapted to slide in co-action with a braking mechanism. Application of the braking mechanism causes oil flow to increase shock absorber damping and reduce diving.
U.S. Pat. No. 4,367,882 entitled "Suspension Apparatus" discloses a suspension apparatus on the front wheel of a motorcycle wherein a hydraulic cylinder is attached between the suspension and the front wheel for converting the frictional force from any substantial braking to an approximate proportional hydraulic force with adjustable damping means for applying the hydraulic force to the suspension so as to oppose and largely counterbalance the inertial force from braking and reduce front end diving.
U.S. Pat. No. 4,437,678 entitled "Vehicular Suspension" disclosed a suspension which includes adjustment means coupled to the braking mechanism and operable in response to braking torque to increase the resilient loading of the suspension to reduce diving during braking.
U.S. Pat. Nos. 4,295,658 entitled "Front End Shock Absorbing Apparatus For Wheeled Vehicle", 3,774,935 entitled "Pirch Suppressing System", 3,945,664 entitled "Vehicle Hydromatic Suspension System", and 2,856,200 entitled "Vehicle Shock Absorber Brake Dive Arrester" all teach systems for increasing the resilient loading of the suspension to reduce diving during braking.
U.S. Pat. No. 4,159,123 entitled "Motorcycle Braking Mechanism Including Means For Controlling Telescoping Action Of The Front Fork Means" discloses a rod interconnecting the upper portion of the suspension to the brake plate so that braking action applies a torquing force which is translated into a linear force via the rod to reduce downward movement of the fork relative to the slider.
U.S. Pat. No. 2,778,656 entitled "Inertia Controlled Fluid Pressure Suspension For Vehicles" discloses a fluid spring suspension and pendulum weight activated valves for adjusting suspension height and tire presure during cornering and braking to reduce bank and dive of the vehicle.
All but two of the above patents teach increasing damping of the suspension to reduce diving. This is not totally effective as suspension travel is also reduced. The final two patents are directed to elevation of the suspension but do so by means which are either cumbersome or not practical for a variety of vehicles.